(1) Known ports (known
Port): from 0 to 1023, which is closely bound to some services. Usually, the communication of these ports clearly indicates the protocol of a certain service. For example, port 80 has always been HTTP communication.
(2) Registered port (registered
Port): from 1024 to 49 15 1. They are loosely bound to some services. In other words, many services are bound to these ports, and these ports are also used for many other purposes. For example, many systems handle a dynamic port of about 1024.
(3) dynamic and/or dedicated ports (dynamic and/or dedicated)
Port): from 49 152 to 65535. Theoretically, these ports should not be assigned to services. In fact, machines usually allocate dynamic ports from 1024. But there are exceptions: SUN's RPC port starts at 32768.